enhance(frontend): 実験的機能としてTranslator APIを用いた翻訳を実装 (#16600)

* enhance(frontend): 実験的機能としてTranslator APIを用いた翻訳を実装

* remove unused imports

* remove unnecessary console.log

* fix 表記揺れ

* fix lint

packages/frontend/src/pages/settings/other.vue

@@ -102,6 +102,9 @@ SPDX-License-Identifier: AGPL-3.0-only
 						<MkSwitch v-model="enableHapticFeedback">
 							<template #label>Enable haptic feedback</template>
 						</MkSwitch>
+						<MkSwitch v-model="enableWebTranslatorApi">
+							<template #label>Enable in-browser translator API</template>
+						</MkSwitch>
 					</div>
 				</MkFolder>
 			</SearchMarker>
@@ -182,6 +185,7 @@ const devMode = prefer.model('devMode');
 const stackingRouterView = prefer.model('experimental.stackingRouterView');
 const enableFolderPageView = prefer.model('experimental.enableFolderPageView');
 const enableHapticFeedback = prefer.model('experimental.enableHapticFeedback');
+const enableWebTranslatorApi = prefer.model('experimental.enableWebTranslatorApi');
 
 watch(skipNoteRender, () => {
 	suggestReload();

packages/frontend/src/preferences/def.ts

@@ -516,4 +516,7 @@ export const PREF_DEF = definePreferences({
 	'experimental.enableHapticFeedback': {
 		default: false,
 	},
+	'experimental.enableWebTranslatorApi': {
+		default: false,
+	},
 });

packages/frontend/src/utility/get-note-menu.ts

@@ -3,7 +3,6 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
-import { defineAsyncComponent } from 'vue';
 import * as Misskey from 'misskey-js';
 import { url } from '@@/js/config.js';
 import { claimAchievement } from './achievements.js';
@@ -27,6 +26,11 @@ import { prefer } from '@/preferences.js';
 import { getPluginHandlers } from '@/plugin.js';
 import { globalEvents } from '@/events.js';
 
+const isInBrowserTranslationAvailable = (
+	'LanguageDetector' in window &&
+	'Translator' in window
+);
+
 export async function getNoteClipMenu(props: {
 	note: Misskey.entities.Note;
 	currentClip?: Misskey.entities.Clip;
@@ -285,13 +289,48 @@ export function getNoteMenu(props: {
 
 	async function translate(): Promise<void> {
 		if (props.translation.value != null) return;
-		props.translating.value = true;
+		if (prefer.s['experimental.enableWebTranslatorApi'] && isInBrowserTranslationAvailable && appearNote.text != null) {
-		const res = await misskeyApi('notes/translate', {
+			props.translating.value = true;
-			noteId: appearNote.id,
+			try {
-			targetLang: miLocalStorage.getItem('lang') ?? navigator.language,
+				// @ts-expect-error 実験的なAPIなので型定義がない
-		});
+				const detector = await LanguageDetector.create();
-		props.translating.value = false;
+				const langResult = await detector.detect(appearNote.text);
-		props.translation.value = res;
+				let localStorageLang = miLocalStorage.getItem('lang');
+				if (localStorageLang != null) {
+					localStorageLang = localStorageLang.split('-')[0];
+				}
+
+				// 翻訳元と翻訳先の言語が同じ場合はTranslatorがthrowするのでそのまま返す
+				if (langResult[0]?.detectedLanguage === localStorageLang || langResult[0]?.detectedLanguage === navigator.language) {
+					props.translation.value = {
+						sourceLang: langResult[0]?.detectedLanguage ?? 'unknown',
+						text: appearNote.text,
+					};
+					return;
+				}
+
+				// @ts-expect-error 実験的なAPIなので型定義がない
+				const translator = await Translator.create({
+					sourceLanguage: langResult[0]?.detectedLanguage,
+					targetLanguage: localStorageLang ?? navigator.language,
+				});
+				const translated = await translator.translate(appearNote.text);
+				props.translation.value = {
+					sourceLang: langResult[0]?.detectedLanguage ?? 'unknown',
+					text: translated,
+				};
+			} finally {
+				props.translating.value = false;
+			}
+		} else if ($i?.policies.canUseTranslator && instance.translatorAvailable) {
+			props.translating.value = true;
+			const res = await misskeyApi('notes/translate', {
+				noteId: appearNote.id,
+				targetLang: miLocalStorage.getItem('lang') ?? navigator.language,
+			});
+			props.translating.value = false;
+			props.translation.value = res;
+		}
 	}
 
 	const menuItems: MenuItem[] = [];
@@ -349,7 +388,7 @@ export function getNoteMenu(props: {
 			});
 		}
 
-		if ($i.policies.canUseTranslator && instance.translatorAvailable) {
+		if ((prefer.s['experimental.enableWebTranslatorApi'] && isInBrowserTranslationAvailable) || ($i.policies.canUseTranslator && instance.translatorAvailable)) {
 			menuItems.push({
 				icon: 'ti ti-language-hiragana',
 				text: i18n.ts.translate,